1. Field of the Invention
The present invention relates to the field of communications, and more particularly to an apparatus and a method for provisioning distribution channels in a communications network.
2. Description of Related Art
Using digital loop carrier (DLC) technology, telephone companies are now able to efficiently serve large numbers of subscribers and expand the capacity of their networks. In contrast to a conventional local loop, i.e. a voice frequency (VF) channel formed by running copper wire pairs between each subscriber and a central office, a DLC system connects a number of subscribers to a central office through high-bandwidth digital transmission lines, such as fiber-optic or T1 lines. Next Generation Digital Carrier Loop (NGDLC) systems include time slot interchange (TSI) capability, which allows the service provider to establish and change connections between subscribers and digital distribution channels.
For a typical high-bandwidth transmission line, a plurality of digital channels, e.g., for carrying VF signals from a plurality of telephones, are provided on a single line by time division multiplexing. For example, a DS-1 (Digital Signal Level 1) format T1 line provides 24 digital channels by dividing time frames into 24 time slots to achieve a transmission rate of 1.544 Mbps (64 kbs per channel plus an 8 kbps control channel, which for an Extended SuperFrame (ESF)-type T1 line is divided into a 2 kbps framing channel, a 2 kbps Cydic Redundancy Check (CRC) channel, and a 4 kbps message channel, called the Facility Data Line).
One particular network configuration which incorporates NGDLC technology uses high-bandwidth transmission lines, such as a group of fiber-optic or T1 lines, to connect a central office (CO) to each of a plurality of remote terminals (RTs), thereby forming a feeder network, and connect a number of distant terminals (DTs) to each RT, thereby forming a distribution network. A DT typically provides voice and/or data services to a number of subscribers in a local geographic region, such as a residential neighborhood, a college campus, or a business facility, and serves as an interface between various information sources/destinations (“drop points”), such as telephone, fax machines, local area networks (LANs), etc., and the digital transmission line connected to an RT. In this configuration, an RT cross-connects distribution channels, i.e., the time-division multiplexed digital channels provided on the high-bandwidth transmission line(s) between DTs and an RT, with feeder channels, i.e., time-division multiplexed digital channels provided on the transmission line(s) between an RT and the central office.
The telephone company controls how the time-division multiplexed feeder and distribution channels (e.g., time slots of a DS-1 format T1 line) are allocated by setting the cross-connections of TSI units at the RT and the DT, respectively, and storing cross-connection information in an administrative database. For example, a certain number of distribution channels may be allocated for serving telephone drop points, while other distribution channels are allocated for serving other types of drop point, such as a LAN or a Private Branch Exchange (PBX), by making the appropriate TSI settings. Cross-connection tables, which can be remotely accessed by the telephone company via a data link, are stored in memory to control the TSI units of the RT and the DT to properly provision the available distribution channels.
Although telephone companies typically manage the TSI units at each DT of a network configuration remotely, a subscriber that needs to change their distribution channel allocation must send a service order to the telephone company before a new channel allocation can be implemented. Since this provisioning requires that the telephone company be involved, however, it often takes several days, if not several weeks, to occur after the service order is placed.